The X-Men's past, present and future collide in this 50th anniversary event! Something horrible happens to the past versions of the X-Men that shakes spacetime to its core - and more X-Men arrive from the future with a message: The original five must return home! But when young Cyclops and Marvel Girl run away to stay in the present, the hunt is on! With space-time up for grabs, the surprise ending will change everything, as the X-Men's footing in the world is drastically altered!